Tack: the direction which is being sailed, normally either starboard tack or port tack. In a starboard tack the wind is coming in from the rider's starboard (right-hand) side, similar to sailing a boat. In normal riding, the kitesurfer takes a heading which is as close to into the wind as possible, and in any event leads at some angle slightly upwind, sometimes as much as 45 degrees; jumping or wave riding usually results in traveling downwind, so the net result is to maintain relative position. (source Wikipedia)